<!DOCTYPE html>
<html>
<head>
	<meta charset="utf-8">
	<title>demo</title>
	<style type="text/css">
		/*代码初始化*/
		/*1、去除浏览器默认添加的内外边距*/
		*{
			/*margin: 0;
			padding: 0;*/
		}


		/*body, div, dl, dt, dd, ul, ol, li, h1, h2, h3, h4, h5, h6, pre, code, form, fieldset, legend, input, textarea, p, blockquote, th, td, hr, button, article, aside, details, figcaption, figure, footer, header, hgroup, menu, nav, section 
		{
		    margin: 0;
		    padding: 0;
		}*/


		/*2、a链接下划线*/
		a{
			text-decoration: none;
		}
		/*3、去除默认列表标记*/
		li{
			list-style-type: none;
		}
		.nav{
			width: 100%;
			height: 60px;
			background: rgba(0,0,0,.1);
			padding: 20px;
			border:1px solid red;
			/*IE盒模型*/
			box-sizing: border-box;
		}
	</style>
</head>
<body>
	<!-- 命名语义化 -->
	<div class="nav"></div>
</body>
</html>

